Bryological and Lichenological Section/ABLS
Simpson, Michael , Dale, DR. M.R.T. .
Differential seedling survival on boreal feather moss remains burned in a forest fire.
In Alberta’s boreal forests, mosses could have a significant impact on tree regeneration after fire. In the exposed environment of a recently burned stand, patches of living moss that remain moist for longer periods than open soil might provide an ameliorated microclimate for seeds. They could also protect seeds from predation and displacement by wind. Species such as Ceratodon purpureus and Funaria hygrometrica have been shown to form associations with nitrogen-fixing microbes, possibly producing small-scale nitrogen oases. But mosses need not be living to be important. In older stands, low severity fires leave behind the remains of burned feather mosses. My research suggests that this is a hostile substrate for some tree species. A laboratory experiment compared the survival of seedlings of tamarack (Larix laricina) and white spruce (Picea glauca) on burned moss and mineral soil. After 4 weeks there was no statistically significant difference between substrates for spruce, but for tamarack mortality on burned moss was twice that on mineral soil, and tamarack seedlings were almost twice as likely to have died as those of spruce. Burned moss has low absorptive capacity and may elevate seeds above the soil. The extent and composition of burned moss early in succession could contribute to the spatial heterogeneity of the canopy at the landscape scale by influencing the success with which some tree species establish in the initial post-fire cohort. Tamarack must colonise by seed and reach the canopy before it can be shaded out. Hence, it might be restricted to areas where fire was severe enough to leave no burned feather moss. The results of this experiment suggest that mosses can have a significant effect upon post-fire succession in coniferous boreal forests and should not be ignored in attempts to emulate natural disturbance.
Quicknote for Foothills Model Forest, Alberta
1 - University of Alberta, Department of Biological Sciences, CW 405 Biological Sciences Building, Edmonton, Alberta, T6G 2E9, Canada
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM